蜂巢晶格反铁磁材料的自旋动力学  

Spin Dynamics of Antiferromagnetic Materials with Honeycomb Lattice

作　　者：潘婧 潘江扬 龚子瑶 吴天兵 王含 蓝郁 PAN Jing;PAN Jiang-yang;GONG Zi-yao;WU Tian-bing;WANG Han;LAN Yu(College of Physics and Electronic Engineering,Hengyang Normal University,Hengyang 421002,Hunan,China)

机构地区：[1]衡阳师范学院物理与电子工程学院,湖南衡阳421002

出　　处：《喀什大学学报》2021年第3期36-39,共4页Journal of Kashi University

基　　金：衡阳师范学院大学生创新创业训练计划项目“六角蜂巢晶格材料物理性质的研究”(cxcy1967)。

摘　　要：魔角石墨烯超导电性的发现使人们对石墨烯等蜂巢晶格材料的研究再次升温.魔角石墨烯的超导电性与铜氧化物高温超导体的超导电性有很多相似之处,而铜氧化物超导体的自旋激发对其超导电性有重要的影响,故研究石墨烯这样的蜂巢晶格材料的自旋激发特性,对理解魔角石墨烯的超导电性有重要的促进作用.利用格林函数理论讨论了蜂巢晶格反铁磁材料的自旋动力学.结果表明,蜂巢晶格反铁磁材料的最近邻和次近邻关联函数均随温度的升高而逐渐降低,次近邻关联函数比最近邻关联函数弱得多,并在高温极限时趋于零;系统的自旋激发谱和动力学自旋结构因子因两个子格子的相互作用而劈裂为成键态和反键态两支,在布里渊区中心附近成键态自旋激发谱与波矢成正比,而反键态支则偏离正比关系;成键态和反键态动力学自旋结构因子在布里渊区中心周围出现磁散射峰,并且随着能量的增加磁散射峰远离布里渊区中心.Materials with honeycomb lattice like graphene are gaining increasing interest again due to the discovery of superconductivity in magic-angle graphene. There are many similarities between the superconductivity of magic-angle graphene and that of cuprate superconductors,and spin excitations are believed to have important impact on superconductivity of cuprates,so study on properties of spin dynamics of honeycomb lattice materials will promote the understanding of their superconductivity. This paper has discussed the properties spin dynamics of honeycomb lattice materials by employing Green’s function theory. Our results demonstrated that:both the correlation function between the nearest-neighbor sites and the correlation function between the next-nearestneighbor sites decrease with increasing the temperature,and the correlation function between the next-nearestneighbor sites is much weaker than that between the nearest-neighbor sites and will approaches zero in hightemperature limit;the spin excitation spectrum and dynamical spin structure factor are both split into the bonding and antibonding components,respectively. Near the center of Brillouin zone,the bonding spin excitation spectrum is proportional to the value of the wave vector,while the antibonding component deviates the proportional relationship. Both the bonding and antibonding dynamical spin structure factor exhibit magnetic scattering peaks around the center of the Brillouin zone and these peaks move away from the center of the Brillouin zone with increasing the energy.

关 键 词：蜂巢晶格 反铁磁 关联函数 自旋激发谱 动力学自旋结构因子 

分 类 号：O469[理学—凝聚态物理]